O’Brien joins a cast that includes Peter Weller as Batman, Michael Emerson as the Joker, Mark Valley as Superman, Ariel Winter as Robin, David Selby as Gotham City police commissioner James Gordon and Michael McKean as Dr. Wolper, the Joker’s Arkham psychiatrist.

“I’ve got a great affection for animation,” O’Brien said. “I’ve always been interested in drawing, and I grew up on the Warner Bros. cartoons  which is where I think I learned a lot of my comedy. I think I got a lot of my comedic timing from the Road Runner and Bugs Bunny cartoons.”